Paper reel brake



April 18, 1944. w. HOPPE PAPER REEL BRAKE Filed Jan. 10, 1942 INVENTORMun/V1701: BY I @v M ATTORNEYS Patented Apr. 18, 1944 rim REEL BRAKEWilliam liioppe, Loneadow;

National Bread Wrapping Machine (30., field. Mass, a corporation ofMassachusetts Mass, assignor to Spring- Appiicatlon January 10, 1942,Serial No. 426,271

(Cl. l8883) s'ciaims.

lem of maintaining a. uniform tension is present when the web is uously.

One object of my invention is to provide a braking device which will, ascompared with prior art devices, more nearly approach the ideal ofapplying a. decelerating braking torque which will at all times bringthe roll to rest after each feeding operation without overrunning of theroll and without an excessive degree of tension on the web.

A further object is to secure the above desirable result conditions. 7

The invention will now be described with relation to the accompanyingdrawing, in which Fig. 1 is a side elevation of a vided with theimproved brake;

Fig. 2 is a detail thereof, partly in section and with the parts in aposition corresponding to a nearly exhausted reel; and

Fig. 3 is a side elevation of a portion of the mechanism.

It may be shown bring a paper reel to rest with a given overrun a brakeshoe against the surface of the web reel by a force which proportionalto the cube of the radius.

For this purpose the reel in is provided with a friction roll H having asurface of rubber The yoke 42 is pivoted at Hi to a bell crank l5swinging on a pivot shaft 46. The short arm H of the bell crank iscoupled by atension spring 48 with an adjusting screw i9 carried on astationary arm 20 and held in adjusted position by a lock nut M. Theyoke i2 normally swings difiering lengths. sized hole 21 in the bellcrank to limit the oscillatory motion of the yoke.

As previously stated, it i desirable to have the decelerating torqueexerted into an overserve for all practical purposes. The torque on thebell crank pivot is thus doubly proportional to the reel radius; or, inother words, proportional to the square of this radius. It acts upon 1!the tension on the web is to be varied, or if I reels or diflerlnglengths are to be used, the screw l8 may be turned to change the initialdegree of stretching of the spring l8, leavingall the otherproportionality factors unchanged. or a fine adjustment may be readilysecured by tuming the screw 25.

What I claim is:

i. A brake for a reel of web material including a member irictionallyengagin the surface of the material on the reel to exert a drag upon therotation of the reel, 9. support carrying the member for movement towardand from the axis of the reel of material as the reel diameter varies,and a spring connected at one end to said support and at its other endto a relatively fixed point, the points or connection of the springbeing so positioned that the extension of the spring decreases directlyand progressively with a decrease in the size or the reel andsimultaneously the component or spring tension causing moveirictionblock carried ment of the support towards the reel decreases relative tothe total force exerted by the spring.

2. A web reel brake comprising a bell crank, a friction block carried byone arm of the bell crank, a rriction roll movably mounted on the bellcrank to be pressed thereby against the reel and having a portionengageable with the block,

.a support, and a spring stretched between the support and the secondarm of the bell crank, the second arm of the bell crank being positionedon that side or the line joining the bell crank pivot and thesupport-carried end of the spring remote from the first arm or the bellcrank.

3. A web reel brake comprising a bell crank, a by one arm or the bellcrank, a friction roll movably mounted on the bell crank to be pressedthereby against the reel and having a portion engageable with the block,a support, a spring stretched between the support and the second arm ofthe bell crank, the second arm or the bell crank being positioned onthat side of the line Joining the bell crank pivot and thesupport-carried end of the spring remote from the first arm of the bellcrank, and an adjustable spring compressible between the first arm ofthe bell crank and the -friction roll to vary the pressure of therriction roll against the block.

WILLIAM HOPPE.

